1. Field of the Invention
The present invention relates to apparatus for placing bands on containers and more particularly to an apparatus for automatically forming and positioning a band about the periphery of large sized containers. The invention further relates to a method and apparatus for more efficiently forming open cylindrical bands from continuous lengths of banding material.
2. Backqround of the Art
Several machines and devices have been developed for cutting and mounting bands of shrinkable materials onto a variety of containers for sealing the containers. While other materials have been used, a preferred material is a thermosetting plastic which is typically fed as continuous lengths into a machine where it is cut into separate cylindrical bands, deposited on target containers, and subsequently contracted through the application of heat to form a tightly fitting seal.
Examples of machines for cutting and mounting heat shrinkable plastic bands are found in U.S. Pat. Nos. 2,623,673, and 2,751,735 and my earlier U.S. Pat. No. 3,802,152. These machines show a variety of mechanisms for receiving plastic tubing material and cutting it into small bands for application to small bottles. In each of these machines the target container rests in a fixed alignment position and the newly formed band is transported to a container where it is deposited over an upper neck or cap portion.
Bands formed and applied in this manner provide a safety seal and often improve container appearance and marketability. Instructions or labeling information can also be imprinted on the bands, which can be made to encircle large portions of the target container in addition to the neck or cap.
Unfortunately, most large size or scale containers of interest have container diameters or perimeters much larger than that accommodated by current banding apparatus designs as exemplified by the above referenced patents. The large, and often irregular, shapes required for large scale containers preclude the use of simple, circularly symmetric or cylindrical, band transport mechanisms adjacent to the containers. Larger "rings" or bands of thin plastic material are not rigid enough to be easily moved or transferred by mechanical means onto containers and tend to collapse before they can be placed on the containers. It is generally believed that very complicated and large apparatus would be required for handling such tasks which would prove unreliable and costly to implement.
In addition, there are many new banding applications requiring the use of bands on containers having lids or tops that are wider or larger in diameter than the remainder of the container. Unlike prior applications, where a wider lower portion of a container could be used to hold the band until shrunk, these bands simply fall to the bottom of the container. To counter this it was believed that complicated apparatus was needed.
Therefore, what is needed is a machine or apparatus capable of automatically placing a large diameter sealing or joining band of shrinkable material around the outside of a substantial portion of large containers. It is desirable that any such apparatus be designed to handle a variety of container or object types and sizes and to efficiently handle flattened banding material. It would be highly advantageous if the banding apparatus accommodated containers having larger lids, tops or mouths, than the remainder of the container without requiring unduly complex apparatus.